Treblinka was a Nazi extermination camp located in German-occupied Poland during World War II. It is estimated that between 700,000 and 900,000 Jews and tens of thousands of Romani people were murdered at Treblinka between July 1942 and October 1943.
However, Treblinka was not a typical concentration camp with long-term prisoners. Rather, it was designed specifically for the mass murder of Jews and other groups deemed "undesirable" by the Nazi regime. As such, the vast majority of those who were brought to Treblinka were immediately sent to the gas chambers upon arrival, and very few survived.
So while Treblinka did have a significant number of inmates pass through its gates during its operation, it is not accurate to describe it as a camp with a specific number of long-term inmates.